对球墨铸铁中合理稀土用量的再认识

介绍了稀土在球墨铸铁中的作用原理.通过各种稀土用量的生产实例,论证了合理的稀土用量范围:(1)对于冲天炉熔炼,出铁温度1 450～1 500℃,原铁液w(S) 0.04％～0.06％,生产汽车、柴油机、农机等中小型球墨铸铁件时,球化剂中w(Mg)在6.5％～7.5％,出铁温度高取下限,反之取上限；加入一定量稀土对质量有一定好处,但不宜过多,w(RE)在1.5％～2.5％,薄小件或壁厚大于50 mm时取下限.(2)中频感应电炉熔炼,铁液温度1 500～1 550℃,原铁液w(S) 0.02％左右,浇注上述类型的产品时,球化剂中w(Mg)在5.5％～6.5％、w(RE)在0.8％左右为宜.(3)冲天炉熔炼浇注厚大球墨铸铁件,球化剂中w(Mg)在6.5％～7.5％,稀土总量1.0％～1.2％,并应以重稀土为主.(4)中频感应电炉熔炼浇注厚大球墨铸铁件,球化剂中w(Mg)在5.5％～6.5％,w(RE)在0.6％～0.8％,也要以重稀土为主.强调指出球墨铸铁中稀土用量过高,不但提高成本、消耗国家宝贵资源,而且对铸件质量不利.     

提高铸态球铁高韧性的试验

为提高球铁高韧性能,试验了下列措施:①采用冲天炉与电炉双联熔炼工艺,进行两次脱硫获得高温、低氧化、低硫的优质铁液;②选用合理的化学成分;③选用低稀土FeSiMgSRE3球化剂;④使用盖包法球化处理工艺.结果是25mm厚Y试块的σb达到457.5～483.3 MPa,δ达到20.7%～24.5%.     

汽车用铸态高韧性中小球铁铸件的试验研究

采用中频感应电炉熔炼获得了高温、低硫、低氧化的优质铁液。合理地设计了铁液化学成分,选用低稀土低镁FeSiMg6RE2球化剂进行盖包法球化处理,用含Ba的多元微量复合孕育剂进行孕育处理,稳定生产出了铸态高韧性QT450-18球铁。结果表明,铸件本体的抗拉强度达到456.3~500.6 MPa,伸长率达到18.4%~19.2%。     

摇包脱硫工艺参数的优化试验

在冲天炉-感应电炉熔炼条件下,为降低球铁原铁液w(S)量,确保球化处理效果稳定,采用摇包脱硫工艺进行脱硫.对原铁液w(S)量和温度、脱硫剂加入量、摇包脱硫时间、脱硫至扒渣时间间隔等因素对脱硫效率的影响进行了试验,最后确定最佳的工艺为:脱硫温度1 470～1 490 ℃,复合脱硫剂加入量1.1%～1.4%,脱硫时间3～3.5 min,脱硫结束后3 min内扒渣.     

铸态高韧性汽车用球铁铸件的试验研究

为获得高韧性球铁,采用中频感应电炉熔炼,获得高温、低硫、低氧化的铁液;合理设计铁液化学成分;选用低稀土FeSiMg8RE3球化剂;采用盖包法球化处理工艺,用含Ba的多元微量复合孕育剂进行孕育处理。结果表明,25 mm厚Y试块的抗拉强度达到456.3⁵00.6 MPa,伸长率达到18.4%500.6 MPa,伸长率达到18.4%¹9.2%。     

用喂线法工艺生产厚大球墨铸铁件

采用冲入法和喂线法两种球化处理工艺生产厚大球墨铸铁件，对比结果认为，喂线法主要有如下优点：①球化剂和孕育剂加入量精确度高；②球化反应在处理包底部进行，有利于球化稳定；③球化剂w（Si）量低，可提高原铁液w（Si）量，多用回炉铁；④可以集中除尘、排烟，并可实现机械化操作。     

φ600×1500mm大断面球墨铸铁件的试制

大断面球铁件的生产，一般都是采用工频炉（电弧炉）熔炼或冲天炉一电炉双重熔炼．针对我国目前球铁生产仍以酸性炉衬和使用冶金焦的冲天炉为主，且普遍存在出铁温度低（＜1440℃）、含硫量高（＞0．06％）的生产状况，我们通过采取一定的工艺措施，取得了冲天炉熔炼浇注￠600×1500mm大断面球铁件的成功，在国内具有推广应用价值．1试件技术要求球铁牌号为QT600—3．在试件本体距上、下端面150mm的两截面上沿1／2半径四周的任意位置取样，其σb≥550N／mm2、δ≥2．5％、HB200～260（粗车后）；球化级别1～3级、石墨大小5～6级（个别4级…     

断面模数为150mm的铸态珠光体球铁

本文叙述铸件尺寸为600×1400mm、总重为3．9t的铸态珠光体球铁的试验工艺和解剖情况。原铁水用工频电炉熔炼。碳化钙脱硫，冲入法球化处理，瞬时孕育，铁型内成型。在铸件凝固阶段，测定了顶部热节圆中心的冷却曲线。铸件去应力处理后用超声波仪测定声速。实体解剖后再次测定声速，分析化学成分，并作硫印、酸洗、力学性能以及金相的测定工作。一、试验1．熔炼与浇注（1）原材料新生铁：本溪Q10；废钢：08～20或05F～20F边角料；球化剂：低稀土镁球化剂、无硅球化剂；脱硫剂：0．l～lmm碳化钙；孕育剂：75硅铁；合金：电解铜和自制合金。…     

提高球铁曲轴材料综合性能的试验

为提高球铁曲轴材料的综合性能,试验了下列措施：①采用感应炉熔炼,净化铁液;②选用合理的化学成分,加入适量的Cu、Mo合金元素;③选用低稀土球化剂FeSiMg8RE3;④采用盖包球化处理法和复合孕育处理;⑤采用部分奥氏体化正火处理.结果是25 mm厚Y试块的σb达到836.6～844.6 MPa,δ达到5.2%～7.4%.     

用10t／h冲天炉生产30t大型铸件的熔炼控制

C5240×40立车立柱铸件，铸件重30t，长4m，浇注铁液量34t。用10t／h冲天炉单独熔炼。存在如何保证34t的铁液量和铁液的浇注温度等难点。1生产条件铁液用10t／h两排大间距冷风冲天炉熔炼。10t浇包和20t浇包浇注。PY45型数字温度计和快速热电偶测温。焦炭为镇江铸造焦。技术要求：力学性能：σb≥250MPa190～235HB。金相组织：A型石墨，长度5～6级。基体组织为细片状珠光体，含量大于95％。2工艺参数炉料配比：Z14生铁25％，回炉料30％，废钢45％。化学成分（％）：2．9～3．1C，1．3～1．6Si，0．9～1．1Mn，＜0．12P，＜0．1S，0．4…     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.